Cannabinoid receptor antagonists

ABSTRACT

This invention discloses methods of using certain aryl-benzo[b]thiophene and benzo[b]furan compounds to block or inhibit cannabinoid receptors in mammals. It also discloses novel compounds which are antagonists of the cannabinoid receptors and also discloses pharmaceutical formulations which contain the compounds as an active ingredient.

This is a continuation-in-part of U.S. patent application Ser. No.08/275,895 filed on Jul. 15, 1994, abandoned.

FIELD OF THE INVENTION

This invention relates to aryl-benzo[b]thiophene and benzo[b]furancompounds which are active antagonists of the CB-1 (cannabinol-1)receptor in the mammalian central nervous system.

BACKGROUND OF THE INVENTION

Cannabinoids are compounds derived from the cannabis sativa plant whichis commonly known as marijuana. The most active chemical compound of thenaturally ocurring cannabinoids is tetrahydrocannabinol (THC),particularly (-)-Δ⁹ -THC. This compound was isolated and identified inthe 1960's and since that time there has been an ever increasingscientific investigation of the effects and pharmacology of thecannabinols. However, prior to discovery of THC, the effects andpharmacology of marijuana use have been known for several thousandyears. Both the uses and abuses of marijuana are recorded from theearliest human records. Marijuana based medicants have been known forcenturies and have been a mainstay of many folk, herbal remedies.

Among the many beneficial pharmacological properties attributed tomarijuana are: analgesia, lowering blood and intra-ocular pressure, andanti-emetic activity in both mammals and man. Indeed, currently, thereis much debate over whether marijuana use should be legalized in certaincases, such as its use in cancer patients for ameliorating the nauseainduced by chemotherapy or to lower intra-ocular pressure in glaucomapatients. After the elucidation of THC, several synthetic compounds werediscovered and have been used clinically for the treatment of cancerpatients, among these are: Nabilone, Nabortate and Levonantrodol.However, although these drugs are useful, they have to a greater orlesser extent some of the negative pharmacologic properties of THC andthus, are limited in their general use.

As marijuana's beneficial effects have been long known, so to itsnegative effects have been well documented. Notable in the negativepharmacology associated with marijuana (and later shown to be associatedwith THC) are: psychological distortions of perception, loss ofshort-term memory, loss of motor coordination, sedation, and euphoria.Long term use of marijuana is considered by many to lead to addiction.Throughout the long history of marijuana its use and abuse have beenintertwined.

Until the 1980's, the mechanism by which the cannabinols, mostspecifically THC, acted on the central nervous system was obscure. Withthe advent of very potent, radiolabelled, synthetic THC agonists (CP55,940, HU210, and HU211), the search for the molecular basis of THCpharmacology began to be elucidated.

In 1988, it was determined that there was a specific receptor whichbound Δ⁹ THC as well as the other synthetic agonists. Using radioautography, the cannabinol receptor was found to be localized in thehippocampus area of the rat brain (see: Herkenham, M., Ann. NY Acad.Sci., 645: p. 19-32 (1992) and references therein). (For a review ofthis chronology, see: Mechoulam, R., et al., CNS Drugs, 2(4), p. 255-260(1994)). Subsequently, it was discovered that there was another,distinct receptor which appears to be primarily located in theperipheral tissues, especially in the immune system (see: Lynn, A. B.and Herkenham, M., J. Pharm. and Exp. Ther., 268(3), p. 1612-1623(1994)). Both receptors have been purified, amino acid sequenced,cloned, and expressed in experimental cell lines. The two receptorswhich bind both the cannabinoids and their synthetic agonists have beendesignated as: CB-1, the receptor located in the central nervous system,and CB-2, the receptor found in peripheral tissues. It is generallyagreed that much of the cannabinoid pharmacology, associated with itscentral nervous system effects and which is most germane to thisinvention, is directly related to the action of the CB-1 receptor.Synthetic and natural compounds which are agonists of the CB-1 receptor,demonstrate the expected experimental and human pharmacology, whileclosely related compounds which bind poorly to CB-1 do not. (For areview of these findings, see: Mechoulam, R., et al., Biochem. Pharm.,48(8), p. 1537-1544 (1994)).

In 1992, it was discovered that the endogenous ligand for the CB-1receptor is anandamide, N-ethanolamine amide of arachidonic acid (see:Devane, W. A., et al., Science, 258, p. 1946-1949. (1992)). Thediscovery of this new neurotransmitter has initiated an intenseinvestigation into the regulation and pharmacology of anandamide.Preliminary results indicate that animals treated with exogenousanandamide demonstrate behavior similar to those treated withcannabinoids. Because of the parallelism of cannabinoid and anandamidepharmacology and the area of the location in the brain of the CB-1receptor, there is a growing body of evidence that anandamide is a keyregulator of functions such as sensory perception, cognition, memory,pain perception, and mood modulation. Since it is very clear in humanswhat the agonism of the CB-1 receptor does with cannabinoids, it wouldseem reasonable by the same extrapolation to predict the likelypharmacology of antagonists of the CB-1 receptor would possess.

Therefore, in patients suffering from loss of sensory perception,cognition, and mood changes such as lethargy and depression, conditionswhich are often associated with the use of marijuana, there is a strongimplication that a controlling factor exacerbating these events would bean inappropriately high or unregulated control of anandamide - CB-1interaction. An anandamide - CB-1 antagontist would be useful inconditions where patients exhibit these symptoms.

There are two reports in the art of cannabinol receptor partial agonistsor antagonists which are not either anandamide or cannabinoid analogs.The first of these compounds, an aminoalkylindole, a partial agonist,(see FIG. 1) is revealed in Pacheco, M., et al., J. Pharmacol. Exp.Ther., 257, p. 170-183 (1991) and Compton, D. R., et al., J. Pharmacol.Exp. Ther., 263, p. 1118-1126 (1992). The antagonist, a halo-arylpyrazole (SR 141716A) (see FIG. 2), was revealed in a patent applicationEP 0576357A1. The CB-1 antagonist, SR141716A, has been shown to blockthe actions of both cannabinoids and anandamide in in vivo and in vitromodels (see: Rinaldi-Carmons, M., et al., FEBS Letters, 350, p. 240-244(1994)). ##STR1##

SUMMARY OF THE INVENTION

This invention provides a method of antagonizing one or more of theactions of anandamide at cannabiniol-1 receptors in a mammal, whichcomprises administering an effective amount of a compound of formula##STR2## in which

R¹ is C₁ -C₄ alkoxy, trifluoromethylsulfonyloxy, hydroxy or cyano;

R² and R³ are each independently C₁ -C₄ alkyl or C₁ -C₄ alkoxy;

R⁴ is CO, CHOH or CH₂ ; and

R⁵ is O or S, provided that when R¹ is hydroxy, R⁵ is O.

Certain compounds of formula I are believed to be novel and are providedas another aspect of the invention. Accordingly, the present inventionprovides a compound of formula I wherein

R¹ is cyano;

R² and R³ are each individually C₁ -C₄ alkyl or C₁ -C₄ alkoxy;

R⁴ is carbonyl; and R⁵ is oxygen or sulfur.

The invention also provides pharmaceutical formulations which include anovel compound of formula (I) as active ingredient in combination with apharmaceutically acceptable carrier, diluent or excipient.

DETAILED DESCRIPTION OF THE INVENTION

The term "C₁ -C₄ alkyl" represents a straight or branched alkyl chainhaving from one to four carbon atoms. Typical straight or branched C₁-C₄ alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl,isobutyl, sec-butyl and t-butyl.

The term "C₁ -C₄ alkoxy" represents an oxygen atom connected directly tothe C₁ -C₄ alkyl group to form an ether moiety. Examples of C₁ -C₄alkoxy groups include methoxy, ethoxy, propoxy and butoxy.

R¹ is preferably methoxy, trifluoromethylsulfonyloxy, hydroxy or cyano.Most preferably R¹ is cyano.

R² is preferably methyl or methoxy.

R³ is preferably methoxy.

R⁴ is preferably carbonyl.

R⁵ is preferably --O--.

Particularly preferred compounds are those in which R¹ is cyano, R² ismethoxy, R³ is methoxy, R⁴ is carbonyl and R⁵ is O; or R² is methyl, R³is methoxy, R⁴ is carbonyl and R⁵ is O; or R² is methoxy, R³ is methoxy,R⁴ is carbonyl and R⁵ is S.

The compounds of formula I belong to two related chemical groups, thebenzothiophene group and the benzofuran group.

1. Benzothiophene Group

This group of compounds includes all of the compounds where R⁵ is S,shown below: ##STR3##

wherein R¹ -R⁴ are as defined above. Of this group of preferredcompounds, the most preferred compound has the R¹ group is CN; methoxygroups at R² and R³ ; and R⁴ is carbonyl. This substitution defines themost preferred compound,[6-methoxy-2-(4-methoxyphenyl)benzo(b)thien-3-yl][4-cyanophenyl]methanonewhich has the following structure: ##STR4##

The general scheme for synthesizing the preferred benzothiophenecompounds is shown as Scheme I: ##STR5##

Benzothiophene synthesis, such as in the scheme shown above, is alsowell documented in the art. Jones, et al., J. Med. Chem., 1984, Vol. 27,No. 8, pp. 1057-1066, disclose the basic scheme shown above, whilevariations of this scheme are found in U.S. Pat. Nos. 4,133,814;4,358,593; 4,380,635; and 4,418,068.

As shown in the above Scheme I the starting material of4-methoxyacetophenone was brominated in methanol to form the halointermediate shown. An aryl sulfide and base is reacted with thisintermediate to form the diaryl intermediate linked by the sulfur -acetyl bridge. Cyclization of this intermediate to the desired benzo(b)thiophene backbone is achieved by reacting with polyphosphoric acid atelevated temperatures. As shown, the 4-methoxyphenyl moiety tends toarrange via cationic rearrangement to the 2-position of thebenzothiophene.

The 2-aryl-benzo(b) thiophene intermediate is then reacted with an arylacyl halide under Friedel-Crafts conditions. The electrophilicsubstitution takes place primarily on the three position (C₃) of thethiophene ring as shown. To produce the most preferred compound of thisgroup, the 4-methoxy group is substituted by a cyano or nitrile group,which requires the presence of more catalyst due to low electrophility.

2. Benzo(b)furan Group

The general schemes for synthesizing compounds of this group is shownbelow as Scheme II: ##STR6##

The above scheme generally depicts the synthesis of the most preferredcompound of the benzofuran group,[6-methoxy-2-(4-methoxyphenyl)benzo[b]furan-3-yl]-3(4-cyanophenyl)methanone.Synthesis of the 3-(4-methoxyphenyl) intermediate compound is describedin detail by Durani and Kapil, A convenient Synthesis of 2-Aryl-3Aroylbenzo[b]furans, Indian Journal of Chemistry, Vol. 22B, May 1983,pp. 489-490. As shown in Scheme II, 2-hydroxy-4-methoxy benzaldehyde isreacted with a diaryl ketone in a strong acid to form the benzopyriliumsalt intermediate compound shown. This intermediate is then oxidized toproduce the[6-methoxy-2-(4-methoxyphenyl)-benzo[b]furan-3-yl]-3-(4-methoxyphenyl)methanoneintermediate which is well-known in the art.

This intermediate is then dealkylated by a well-known procedure to formthe 4-hydroxy intermediate shown. A two-step process is then employed toconvert the 4-hydroxy moiety to a nitrile group as shown above. Firstthe hydroxy group is converted to a triflate ester derivative and thenthis compound is reacted with a cyanide source in the presence of acatalyst to complete the conversion to the preferred compound. Thegeneral procedure for converting a methoxy moiety to a cyano moiety isshown in part in Chambers and Widdowson, Nickel Catalysed Conversion ofPhenol Triflates to Aromatic Nitriles and Acids, J. Chem, Soc. PerkinTrans. I, 1989, p. 1365. Preferred reagents for the conversion aretriflimide ((CF₃ SO₂)₂ NPhenyl) and triethylamine in a non-polar solventto effect the hydroxy-triflate conversion; acetonitrile, potassiumcyanide, and Nickel-bis-triphenylphosphine chloride with zinc dust metaland triphenyl phosphine to effect the triflate to cyano conversion. Aswith scheme I, derivative compounds of the preferred compound are easilyprepared by one skilled in the art or by the same chemistry.

Other benzo[b]furan derivatives are depicted in Scheme III shown below:##STR7##

The above scheme depicts the synthesis of various benzo[b]furanderivatives with different bridges between the furan ring and the3-(4-methoxyphenyl)ring. As shown in Schemes I and II, the typicalbridge is a carbonyl group. Scheme III depicts the formation of 2different bridge groups, namely, the carbinol and methylene. All ofthese compounds are preferably formed from the(4-methoxyphenyl)methanone base intermediate by the processes shown.Detailed descriptions of these processes, as with all other processes inSchemes I-II may be seen in the specific Examples later in thisspecification.

Finally, the preferred benzo[b]furan compounds can be synthesized viaFriedel-Crafts acylation of the benzo[b]furan intermediate as outlinedgenerally in Scheme IV below, and defined in detail in the specificExamples. ##STR8##

The general procedures for the above Scheme IV are referenced in J.Astoin, J. Heterocyclic Chemistry, 1977, Vol. 14, pp. 861-869.

The specific examples which follow are not to be considered as limitingthe invention, but are merely illustrative of the best mode of synthesisof the most preferred compounds at this time.

EXAMPLE 1

Synthesis of α-(3'-Methoxyphenoxy)-4-methylacetophenone

51.05 g (0.24 mol) of 4-methyl-α-bromoacetophenone was dissolved in 200mL of anhydrous (dimethyl formamide) DMF and 35 g (0.28 mol) of3-methoxyphenol was added. The reaction mixture was stirred with amechanical stirrer and 80 g (0.58 mol) of anhydrous K₂ CO₃ was added.The reaction was allowed to proceed at ambient temperature and under anatmosphere of nitrogen. After eighteen hours, the reaction mixture wasfiltered to remove the inorganic salts. The DMF was removed byevaporation in vacuo, the resulting thick oil was dissolved in 250 mL ofEtOAc and washed with brine. The EtOAc layer was removed and dried byfilteration through anhydrous Na₂ SO₄ and the solvent was removed byevaporation. The resulting oil was crystallized from Et₂ O, whichyielded 37 g of the title compound as a light yellow solid.

PMR: consistent with the proposed structure

MS: m/e=256 (M+) FD

EA: Calc: C, 74.98; H, 6.29 Found: C, 75.17; H, 6.38

EXAMPLE 2 Synthesis of 6-Methoxy-2-(4-methylphenyl)benzo[b]furan

30 g (0.12 mol) of 2-(3-Methoxyphenoxy)-4'-methylacetophenone wasdissolved in 300 mL of xylene and 45 g of polyphosphoric acid (PPA) wasadded. The reaction mixture was stirred with a magnetic stirrer and keptunder an atmosphere of nitrogen. The reaction was heated to reflux (135°C.) for eighteen hours. The reaction was allowed to cool to about 90° C.and 500 mL of water was added. The reaction was stirred until all thePPA dissolved in the water layer. The xylene layer was removed andextracted twice with water. The xylene layer was dried by filterationthrough anhydrous Na₂ SO₄ and evaporated to remove the solvent. Theresulting solid was crystallized from hot ethyl acetate (EtOAc), whichyielded 5 g of the title compound as a white solid.

PMR: consistent with the proposed structure

MS: m/e=238 (M+) FD

EA: Calc: C, 80.65; H, 5.92 Found: C, 80.57; H, 5.97

C₁₆ H₁₄ O₂ MW=238.29

EXAMPLE 3 Synthesis of[6-Methoxy-2-(4-methylphenyl)benzo[b]furan-3-yl][4-cyanophenyl]methanone

One gram (4.2 mmol) of 6-Methoxy-2-(4methylphenyl)benzo[b]furan wasdissolved 25 mL of dichloromethane and 830 mg (5.0 mmol) of4-cyanobenzoyl chloride was added. The reaction was stirred and keptunder a nitrogen atmosphere. 2.75 mL (25 mmol) of TiCl₄ was slowly addedto the reaction mixture. The reaction was allowed to proceed for fourhours and quenched by the addition of 5 mL of methanol (MeOH). Thesolvents were removed by evaporation and the crude material waschromatographed on a silica gel column eluted with hexane-EtOAc (9:1).The desired fractions were determined by tlc and combined and evaporatedto a solid. The resulting product was crystallized from diethyl ether(Et₂ O). This yielded 325 mg of the title compound as yellow powder.

PMR: consistent with the proposed structure

MS: m/e=368 (M+) FD

EA: Calc: C, 78.46; H, 4.66; N, 3.81 Found: C, 78.28; H, 4.61; N, 3.52.

EXAMPLE 4 Synthesis of[6-Methoxy-2-(4-methoxyphenyl)-benzo[b]furan-3-yl]-3-(4-hydroxyphenyl)-methanone

A suspension of 2 g of[6-Methoxy-2-(4-methoxyphenyl)benzo[b]furan-3-yl]-3-(4-methoxyphenyl)-methanone5.15 mmol) and 1.3 g sodium ethanethiol (15.45 mmol) in 40 mL of DMF washeated to 80° C., checking by TLC 35% ethyl acetate:hexane every 20minutes. When the starting material was consumed after 4 hours, themixture was allowed to cool to room temperature, diluted with 150 mL.ethyl acetate, and washed twice with 1N H₂ SO₄ (100 mL.). The organiclayer was then dried on Na₂ SO₄ and rotovaped to a brown oil, thenpurified by gravity chromatography with silica, 35% ethylacetate:hexane. 1.15 g yield (60%) of the title compound as a brightyellow solid. PChem: NMR QE300 MHz in d6-DMSO: (3.85 ppm, s, 3H), (3.90ppm, s, 3H), (6.85 ppm, d, 2H), (6.95 ppm, dd, 1H), (7.00 ppm, d, 2H),(7.30 ppm, ds, 1H), (7.40 ppm, s, 1H), (7.60 ppm, d, 2H), (7.75 ppm, d,2H).

EXAMPLE 5 Synthesis of[6-Methoxy-2-(4-methoxyphenyl)-benzo[b]furan-3-yl]-3-(phenyl-4-triflate)-methanone

A solution of 1.15 grams (3.07 mmol) of the Example 4 intermediate wasdissolved in 40 mL. of methylene chloride with 0.92 mL. of tri-ethylamine (6.61 mmol). To this was added a solution of 1.15 g of triflimide(3.23 mmol) in 10 mL. methylene chloride over 15 minutes. Afteraddition, the mixture was allowed to stir at room temperature for 48hours. The mixture was then diluted with 100 mL methylene chloride,washed twice with 1N H₂ SO₄, twice with deionized water, twice withsaturated NaHCO₃, then once more with water. Dry on Na₂ SO₄ to yield 1.4grams (89.7%) of the title compound yellow amorphous material. PChem:NMR QE300 MHz in CDCl₃ : (3.80 ppm, s, 3H), (3.90 ppm, s, 3H), (6.75ppm, d, 2H), (6.95 ppm, dd, 1H), (7.10 ppm, ds, 1H), (7.20 ppm, d, 2H),(7.45 ppm, d, 2H), (7.60 ppm, d, 1H), (7.85 ppm, d, 2H). MS FD+=506.

EXAMPLE 6 Synthesis of[6-Methoxy-2-(4-methoxyphenyl)-benzo[b]furan-3-yl]-3-(4-cyanophenyl)-methanone

A solution of 1.1 g of (2.17 mmol) of the Example 5 compound in 4 mL. ofdry acetonitrile with 156 mg KCN (2.39 mmol), 71 mg of nickeltriphenylphosphine dichloride (0.109 mmol), 57 mg of triphenylphosphine(0.217 mmol), and 43 mg of zinc dust (0.652 mmol) was heated to 65° C.for 2 hours. The mixture was then allowed to cool to room temperature,diluted with 100 mL. of methylene chloride, washed twice with water, anddried on Na₂ SO₄. The mixture was then purified on a silica plug withflash chromatography using 100% methylene chloride, rotovaped dry, andcrystallized from 100% ethyl acetate to yield 580 mg of the titlecompound (70%). PChem: NMR QE300 MHz in d6-DMSO: (3.75 ppm, s, 3H),(3.85 ppm, s, 3H), (6.85 ppm, d, 2H), (6.95 ppm, dd, 1H), (7.35 ppm, ds,1H), (7.45 ppm, d, 2H), (7.50 ppm, d, 1H), (7.80 ppm, s, 4H). MSFD+=384. EA calculated for C₂₄ H₁₇ NO₄ (Theory/Found): C, 75.19/75.35;H, 4.47/4.52; N, 3.65/3.66.

EXAMPLE 7 Synthesis of[6-methoxy-2-(4-methoxyphenyl)benzo[b]thien-3-yl][4-methoxyphenyl]methanone

A solution of 1.54 g (9 mmol) of6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophene and 1.62 g (6 mmol) ofp-anisoyl chloride in 100 mL of methylene chloride was prepared andcooled to 0° C. Over 5 minutes, 1.20 g (9 mmol) of AlCl₃ was added insmall portions. After 1 hour, the reaction mixture was poured over 150mL of ice water and extracted three times with 75 mL portions ofmethylene chloride. The methylene chloride extracts were combined andwashed with 30 mL of 1N NaOH, then with water. The organic layer wasdried with magnesium sulfate and evaporated to dryness. The crudeproduct was chromatographed on silica eluted with 30% EtOAc in hexane.The product was crystallized from acetone-methanol. This yielded 2.11 gof the title compound as a light yellow solid.

PMR: consistent with the proposed structure

MS: m/e=404 (M+)

EA: Calc: C, 71.27; H, 4.98; S, 7.93; O, 15.82 Found C, 71.50; H, 5.00;S, 7.98; O, 15.77

C₂₄ H₂₀ O₄ S

EXAMPLE 8 Synthesis of[6-methoxy-2-(4-methoxyphenyl)benzo[b]thien-3-yl][4-hydroxyphenyl]methanone

A solution of 0.4 g (1 mmol) of[6-Methoxy-2-(4-methoxyphenyl)benzo[b]thien-3-yl][4-methoxyphenyl]methanonein 2 mL of DMF was added to a solution of 3 mL of 0.5M sodiumethanethiol in DMF. The reaction mixture was heated to 80° C. for 4hours. The reaction mixture was allowed to cool and diluted with 10 mLof water and 10 mL of EtOAc and neutralized with 1N HCl. The reactionmixture was extracted three times with 30 mL portions of EtOAc. Thecombined organic extracts were washed four times with 20 mL portions ofbrine and dried with MgSO₄ and evaporated to dryness. The crude productwas chromatographed on silica eluting with 30% EtOAc in hexane, andevaporated to dryness. This yielded 0.31 g of the title compound as ayellow solid.

PMR: consistent with the proposed structure

MS: m/e=390 (M+) FD

EA: Calc: C, 70.75; H, 4.65 Found: C, 70.93; H, 4.56

C₂₃ H₁₈ O₄ S

EXAMPLE 9 Synthesis of[6-Methoxy-2-(4-methoxyphenyl)benzo[b]thien-3-yl][4-trifluoromethylsulfonyloxyphenyl]methanone

A solution was prepared of 3 g (7.7 mmol) of[6-methoxy-2-(4-methoxyphenyl)benzo[b]thien-3-yl][4-hydroxyphenyl]methanonein 100 mL of methylene chloride and 1.57 g (15.5 mmol) of triethylamine.A solution of 2.8 g (7.72 mmol) of triflimide in 50 mL of methylenechloride was slowly added to the reaction mixture over a period of 30minutes. The reaction, under an atmoshere of nitogen and at roomtemperature, was allowed to proceed for 16 hours. The reaction mixturewas washed with 100 mL of 1N H₂ SO₄, then three times with 100 mLportions of 2N NaOH and finally with 100 mL of water. The organic layerwas dried with anhydrous Na₂ SO₄ and the product allowed to crystallizeout. This yielded 2.5 g of the title compound as a yellow solid.

PMR: consistent with the proposed structure

MS: m/e=522 (M+) FD

EA: Calc: C, 55.17; H, 3.28 Found: C, 54.37; H, 3.21

EXAMPLE 10 Synthesis of[6-Methoxy-2-(4-methoxyphenyl)benzo[b]thien-3-yl][4-cyanophenyl]methanone

A suspension of 2 g (3.83 mmol) of the compound of example 7 wasprepared in 5 mL of anhydrous acetonitrile with 274 mg (4.21 mmol) ofKCN, 125 mg (0.19 mmol) of nickel triphenylphosphine dichloride, 101 mg(0.38 mmol) of triphenylphosphine, and 38 mg (0.58 mmol) of zinc dust.The reaction mixture was heated to 65° C. for 90 minutes under anitrogen atmoshere. The reaction mixture was allowed to cool to roomtemperature and was diluted with 100 mL of methylene chloride. Thereaction mixture was filtered and washed twice with 150 mL portions ofwater. The organic layer was dried with anhydrous Na₂ SO₄. The crudeproduct was recrystallized twice from MeOH. This yielded 1.1 g of thetitle compound as a yellow powder.

PMR: consistent with the proposed structure

MS: m/e=399 (M+) FD

EA: Calc: C, 72.16; H, 4.29; N, 3.51 Found: C, 71.96; H, 4.33; N, 3.50

C₂₄ H₁₇ NO₃ S

EXAMPLE 11 Alternate Synthesis of[6-Methoxy-2-(4-methoxyphenyl)benzo[b]furan-3-yl][4-cyanophenyl]methanone

A solution of 160 g (0.63 mol) of6-methoxy-2-(4-methoxyphenyl)benzo[b]furan and 154.3 g (0.93 mol) of4-cyanobenzoyl chloride in 3 L of methylene chloride was prepared. Tothis solution, 203.6 mL (1.85 mol) of TiCl₄ was slowly added. Thereaction mixture was heated to reflux under a nitrogen atmoshere for aperiod of four hours. The reaction mixture was poured unto 3 kg of iceand allowed to quench for sixteen hours. The organic layer was separatedand washed twice with 5 L portions of 20% NaHCO₃ solution and finallywashed with 5 L of brine. The organic layer was dried with anhydrousMgSO₄ and evaporated to an oil. The crude product was chromatographed ona silica gel column eluted with 20% EtOAc-CH₂ Cl₂. This yielded 156 g,which was further purified by rechromatography on a silica gel columneluted with 20% EtOAc-Et₂ O and crystallized from the eluting solvent.This yielded 100.1 g of the title compound as a yellow powder.

EXAMPLE 12 Synthesis of6-Methoxy-2-(4-methoxyphenyl)benzo[b]thien-3-yl][4-n-propyloxyphenyl]methanone

A solution of 1.17 g (3 mmol) of[6-methoxy-2-(4methoxyphenyl)benzo[b]thien-3-yl][4-hydroxyphenyl]methanonein 20 mL of DMF was prepared. To the solution was added 1.03 g (7.50mmol) of potassium carbonate and the mixture was heated to 100° C. After15 minutes, 2.73 mL (30 mmol) of 1-bromopropane was added and reactionwas heated for an additional 40 minutes. The reaction mixture wasallowed to cool and filtered. The filterate was added to 25 mL of waterand was extracted three time with 20 mL portions of EtOAc. The combinedextracted were washed with brine, dried with MgSO4 and evaporated to asolid. This yielded an eighty percent yield of the title compound.

PMR: consistent with the proposed structure

MS: m/e=432 (M+) FD

EA: Calc: C, 72.20; H, 5.59 Found: C, 72.00; H, 5.65

C₂₆ H₂₄ O₄ S

EXAMPLE 13 Synthesis of[6-Methoxy-2-(4-methoxyphenyl)benzo[b]thien-3-yl][4-n-butyloxyphenyl]methanone

In a manner identical with example 12, the title compound was preparedin 77% yield as a yellow solid.

PMR: consistent with the proposed structure

MS: m/e=446 (M+) FD

IR: 3011, 2963, 2938, 1599, 1476, 1254, 1166 cm⁻¹ (CHCl₃)

EXAMPLE 14 Synthesis of[6-Methoxy-2-(4-methoxyphenyl)benzo[b]furan-3-yl][4-methoxyphenyl]methanone

The title compound was prepared in a manner similar to that used inexample 3, by using p-anisoyl chloride as the acylating agent.

EXAMPLE 15 Synthesis of[6-Methoxy-2-(4-methoxyphenyl)benzo[b]furan-3-yl][4-methoxyphenyl]methanol

A solution of 1 g (2.56 mmol) of[6-Methoxy-2-(4methoxyphenyl)benzo[b]furan-3-yl][4-methoxyphenyl]methanonewas prepared in 25 mL of THF. To this solution, 1 g (25.4 mmol) ofLiAlH₄ was added in small portions over a 10 minute period. The reactionwas allowed to proceed at room temperature in a nitrogen atmosphere.After sixteen hours, the reaction was quenched by the addition of 5 mLof water. To this suspension was added 3 mL of 15% (w/w) NaOH and anadditional 3 mL of water. This suspension was filtered. The resultingfilterate separated into two layers. The top (organic) layer was removedand evaporated to dryness. The crude product was chromatographed onsilica gel eluted with CHCl₃. This yielded 880 mg of the title compoundas a colorless gum.

PMR: consistent with the proposed structure

MS: m/e=390 (M+) FD

EA: Calc: C, 73.83; H, 5.68 Found: C, 74.10; H, 5.66

EXAMPLE 16 Synthesis of[6-Methoxy-2-(4-methoxyphenyl)benzo[b]furan-3-yl][4-methoxyphenyl]methane

A solution of 400 mg (1.02 mmol) of[6-Methoxy-2-(4-methoxyphenyl)benzo[b]furan-3-yl][4-methoxyphenyl]methanolwas dissolved in 10 mL of n-propylbenzene and 200 mg (5.25 mmol) ofLiAlH4 was added. The reaction mixture was heated to reflux under anitrogen atmoshere for 45 minutes. After sixteen hours, the reaction wasquenched by the addition of 5 mL of water. To this suspension was added3 mL of 15% (W/N) NaOH and an additional 3 mL of water. This suspensionwas filtered. The resulting filterate separated into two layers. The top(organic) layer was removed and evaporated to dryness. The crude productwas chromatographed on silica eluted with 20% EtOAc in hexane. The finalproduct was crystallized from ether. This yielded 100 mg of the titlecompound as a solid with a low melting point.

PMR: consistent with the proposed structure

MS: m/e=374 (M+) FD

Procedures for synthesizing other Formula I compounds are eitherwell-known in the art or are easily converted by following one of theabove procedures with different reagents, dependent upon the desired endcompound.

The compounds of the present invention are preferably formulated priorto administration. Therefore, another aspect of the present invention isa pharmaceutical formulation comprising a compound of formula I and apharmaceutically-acceptable carrier, diluent, or excipient. The presentpharmaceutical formulations are prepared by known procedures usingwell-known and readily available ingredients. In making the compositionsof the present invention, the active ingredient will usually be mixedwith a carrier, or diluted by a carrier, or enclosed within a carrierwhich may be in the form of a capsule, sachet, paper, or othercontainer. When the carrier serves as a diluent, it may be a solid,semi-solid, or liquid material which acts as a vehicle, excipient, ormedium for the active ingredient. The compositions can be in the form oftablets, pills, powders, lozenges, sachets, cachets, elixirs,suspensions, emulsions, solutions, syrups, aerosols, ointmentscontaining for example up to 10% by weight of active compound, soft andhard gelatin capsules, suppositories, sterile injectable solutions, andsterile packaged powders.

Some examples of suitable carriers, excipients, and diluents includelactose, dextrose, sucrose, sorbitol, mannitol, starches, gum, acacia,calcium phosphate, alginates, tragacanth, gelatin, calcium silicate,microcrystalline cellulose, polyvinylpyrrolidone, cellulose, watersyrup, methyl cellulose, methyl and propyl hydroxybenzoates, talc,magnesium sterate and mineral oil. The formulations can additionallyinclude lubricating agents, wetting agents, emulsifying and suspendingagents, preserving agents, sweetening agents, or flavoring agents.Compositions of the inventions may be formulated so as to provide quick,sustained, or delayed release of the active ingredient afteradministration to the patient by employing procedures well known in theart.

The compositions are preferably formulated in a unit dosage form, eachdosage containing from about 5 to about 500 mg, more preferably about 25to about 300 mg of the active ingredient. The most preferred unit dosageform contains about 10 to about 200 mg of the active ingredient. Theterm "unit dosage form" refers to a physically discrete unit suitable asunitary dosages for human subjects and other mammals, each unitcontaining a predetermined quantity of active material calculated toproduce the desired therapeutic effect, in association with a suitablepharmaceutical carrier. The following formulation examples areillustrative only and are not intended to limit the scope of theinvention in any way.

FORMULATION 1

Hard gelatin capsules are prepared using the following ingredients:

    ______________________________________                                                           Quantity                                                                      (mg/capsule)                                               ______________________________________                                        active ingredient    250                                                      Starch, dried        200                                                      Magnesium stearate   10                                                       Total                460     mg                                               ______________________________________                                    

The above ingredients are mixed and filled into hard gelatin capsules in460 mg quantities.

FORMULATION 2

A tablet is prepared using the ingredients below:

    ______________________________________                                                             Quantity                                                                      (mg/tablet)                                              ______________________________________                                        active ingredient      250                                                    Cellulose, microcrystalline                                                                          400                                                    Silicon dioxide, fumed 10                                                     Stearic acid           5                                                      Total                  665    mg                                              ______________________________________                                    

The components are blended and compressed to form tablets each weighing665 mg.

FORMULATION 3

An aerosol solution is prepared containing the following components:

    ______________________________________                                                        Weight %                                                      ______________________________________                                        active ingredient 0.25                                                        Ethanol           29.75                                                       Propellant 22     70.00                                                       (chlorodifluoromethane)                                                       Total             100.00                                                      ______________________________________                                    

The active compound is mixed with ethanol and the mixture added to aportion of the Propellant 22, cooled to -30° C. and transferred to afilling device. The required amount is then fed to a stainless steelcontainer and diluted with the remainder of the propellant. The valveunits are then fitted to the container.

FORMULATION 4

Tablets each containing 60 mg of active ingredient are made as follows:

    ______________________________________                                        active ingredient       60     mg                                             Starch                  45     mg                                             Microcrystalline cellulose                                                                            35     mg                                             Polyvinylpyrrolidone    4      mg                                             Sodium carboxymethyl starch                                                                           4.5    mg                                             Magnesium stearate      0.5    mg                                             Talc                    1      mg                                             Total                   150    mg                                             ______________________________________                                    

The active ingredient, starch and cellulose are passed through a No. 45mesh U.S. sieve and mixed thoroughly. The solution ofpolyvinylpyrrolidone is mixed with the resultant powders which are thenpassed through a No. 14 mesh U.S. sieve. The granules so produced aredried at 50° C. and passed through a No. 18 mesh U.S. sieve. The sodiumcarboxymethyl starch, magnesium stearate and talc, previously passedthrough a No. 60 mesh U.S. sieve, are then added to the granules which,after mixing, are compressed on a tablet machine to yield tablets eachweighing 150 mg.

FORMULATION 5

Capsules each containing 80 mg medicament are made as follows:

    ______________________________________                                        active ingredient       80     mg                                             Starch                  59     mg                                             Microcrystalline cellulose                                                                            59     mg                                             Magnesium stearate      2      mg                                             Total                   200    mg                                             ______________________________________                                    

The active ingredient, cellulose, starch and magnesium stearate areblended, passed through a No. 45 sieve, and filled into hard gelatincapsules in 200 mg quantities.

FORMULATION 6

Suppositories each containing 225 mg of active ingredient may be made asfollows:

    ______________________________________                                        active ingredient       225    mg                                             Staurated fatty acid glycerides                                                                       2,000  mg                                             Total                   2,225  mg                                             ______________________________________                                    

The active ingredient is passed through a No. 60 mesh U.S. sieve andsuspended in the saturated fatty acid glycerides previously melted usingthe minimum heat necessary. The mixture is then poured into asuppository mold of nominal 2 g capacity and allowed to cool.

FORMULATION 7

Suspensions each containing 50 mg of medicament per 5 ml dose are madeas follows:

    ______________________________________                                        active ingredient        50     mg                                            Sodium carboxymethyl cellulose                                                                         50     mg                                            Syrup                    1.25   ml                                            Benzoic acid solution    0.10   ml                                            Flavor                   q.v.                                                 Color                    q.v.                                                 Purified water to total  5      ml                                            ______________________________________                                    

The medicament is passed through a No. 45 mesh U.S. sieve and mixed withthe sodium carboxymethyl cellulose and syrup to form a smooth paste. Thebenzoic acid solution, flavor and color are diluted with some of thewater and added, with stirring. Sufficient water is then added toproduce the required volume.

FORMULATION 8

An intravenous formulation may be prepared as follows:

    ______________________________________                                        active ingredient      100    mg                                              Mannitol               100    mg                                              Purified water to total                                                                              200    ml                                              ______________________________________                                    

A variety of physiological functions have been shown to be influenced bystimulation of the cannabinoid receptors. The formula I compounds of thepresent invention are believed to possess the ability to treat a varietyof disorders in mammals, including humans which are associated withcannabinoid stimulation. Such disorders include, without limitation,depression, cognitive dysfunction, loss of memory and poor alertness andsensory perception. The formula I compounds act as antagonists of thecannabinoid receptors.

Experiments were performed to demonstrate the antagonist activity of theformula I compounds at the cannabinoid receptors. The formula Icompounds were tested for their ability to inhibit binding of[1α,2β-(R)-5α]-(-)-5-(1,1-dimethylheptyl)-2-[5-hydroxy-2-(3-hydroxypropyl)cyclohexylphenol(CP-55,940);and for their ability to increase cAMP accumulation in cells.

Cell Culture and Stable Expression of Cannabinoid Receptor Clones

Chinese hamster ovary cells (CHO) and murine Ltk cells were obtainedfrom The American Type Culture Collection (Rockville, Md.). CHO cellswere maintained in an atmosphere of 5% CO₂ in growth media consisting ofAlpha-MEM substituted with 10% fetal calf serum, L-glutamine (2 mM) andpenicillin (50 U/ml) and streptomycin (50 ug/ml). Ltk cells werecultured at 37° C., in 5% CO₂ in Dulbecco's modified essential medium(0.45% glucose) containing fetal bovine serum (10%), L-glutamine (2 mM),penicillin (50 U/ml) and streptomycin (50 ug/ml). The rat cannabinoidreceptor cDNA was stably expressed in CHO cells. A 2.2 kilobase (kb)Sstl-EcoR1 fragment containing the complete coding region of the humancannabinoid receptor gene was subcloned into the Sstl and EcoR1 sites ofthe pCD-PS vector to created plasmid hSKR6pl which was transfected intoCHO cells using calcium phosphate precipitation. Receptor-containingplasmids were co-transfected with plasmids containing the neomycinresistance gene created in a similar fashion. After transfection, thecells were selected with neomycin and the individual neomycin resistantcolonies grown to establish cell lines. The human cannabinoid (CB-1)cDNA was stably expressed in L cells with the following constructdesigned to amplify receptor expression levels thereby reducing thenumber of cells required for radioligand binding analysis. A 2.2kilobase (kb) Sstl-EcoR1 fragment containing the complete coding regionof the human cannabinoid receptor gene was subclones into the Sstl andEcoR1 sites of the pCD-PS vector to create plasmid hSKR6pl. FromhSKR6pl, a 3.3 kb Sall-Ndel fragment was removed, the ends blunted, andinserted into the blunted Sall site of the plasmid ptkmuARS-4. Theresulting plasmid contained the receptor gene coding sequence flanked bythe SV40 early region promoter and polyadenylation sequence originallyengineered into the cloning vector pCD. This plasmid was transfectedinto murine Ltk cells by calcium phosphate precipitation. Aftertransfection, L cells were selected in HAT medium. IndividualHAT-resistant colonies were isolated after 3-4 weeks, grown toestablished cell lines, and cultured for at least 3 months to allow forexpression of the receptor to stabilize.

Thus, two cell lines were established which expressed the human CB-1receptor, i.e., the CHO and the Ltk.

Plasma Membrane Preparation

Ltk Cells, grown to confluency in 175 cm² culture flasks, were washedonce with cold phosphate buffered saline and scraped in assay buffer (50mM Tris, 5 mM EDTA, 5 mg/mL BSA, pH 7.4) with added 200 mM sucrose.Cells were then centrifuged at 1000×g for 10 minutes at 4° C. Thesupernatant was discarded and the pellet resuspended in ice cold assaybuffer, homogenized with a Tekmar Tissumizer (Cincinnati, Ohio, USA) at95% maximal speed for 30 seconds followed by centrifugation for 15minutes, 2°-4° at 2000×g. The supernatant was centrifuged again for 30minutes at 43,000×g. The pellet was resuspended in minimal volume ofassay buffer containing 200 mM sucrose and stored at -80° until use.

All experiments were performed in glass test tubes, which were treatedby soaking in dichloromethane/toluene (1:10 vol/vol) for 1 hour and thenin methanol for 30 minutes, followed by a final rinse with 100%methanol. Test tubes were then allowed to air dry overnight before use.

Radioligand Binding Assays

Competition and saturation binding assays were performed with [³H]CP55,940 as the labeled ligand. A rapid filtration binding assay wasdeveloped (see: Felder, C. C., et al., Proc. Natl. Acad. Su., 90, p.7656-7660(1993) based on a previously published method with thefollowing modifications. All ligands were diluted in assay buffercontaining 50 mg/mL fatty acid-free BSA, with the final BSAconcentration not exceeding 5 mg/mL. Assay solutions were incubated insilicone-treated test tubes for 1 hr at 30°, with a final assay volumeof 0.5 mL and a final membrane concentration of 40-400 μg of protein/mL.Membranes were rapidly filtered over GF/B filters (Whatman, Maidstone,England) that had been pretreated for 3 hr with 0.1% polyethyleneimine(v/w) (pH 7.4), using an Inotech (Lansing, Mich.) 96 or 48-position cellharvester. Membranes were washed with 3×3 mL of ice-cold wash bufferj(50 mM Tris, 0.5 mg/ml BSA, pH 7.4). Filters containing washedmembranes were transferred to scintillation vials, 1 mL of 0.1% (v/v)Triton X-100 was added to each vial, and vials were incubated overnightbefore addition of scintillation cocktail (Hydrofluor; NationalDiagnostics, Manville, N.J.). Protein concentrations were determinedusing the bioinchoninic acid protein reagent (Pierce, Rockford, Ill.),as described. Binding data were analyzed with the program LIGAND or withprogram GraphPad (GraphPad Software, San Diego, Calif.), which performsweighted nonlinear least squares curve-fitting to the general model ofFeldman.

The results of the potent, specific binding of the compounds of formulaI are demonstrated in Table 1.

                  TABLE 1                                                         ______________________________________                                        Compound         K.sub.i versus [H.sup.3 ] CP55,940                           ______________________________________                                        Example 15       25800     nM                                                 Example 16       5300      nM                                                 Example 4        4120      nM                                                 Example 7        3600      nM                                                 Example 12       1540      nM                                                 Example 8        950       nM                                                 Example 5        490       nM                                                 Example 13       430       nM                                                 Example 3        134       nM                                                 Example 6        170       nM                                                 ______________________________________                                    

Assay of cAMP Accumulation

The purpose of this assay is to be demonstrate the effect of CB-1binding compound on the CB-1 signal tranduction pathway, i.e., toestablish if the binding compound is working as an agonist or antagonistin vitro.

CHO cells were preincubated in growth media with forskolin (10⁻⁶ M) withor without anandamide for 4 hours Cyclic AMP accumulation was measuredover 5 minutes after exchanging the growth media with serum free mediacontaining forskolin (10⁻⁶ M) and anandamide, with or withoutantagonists as indicated. Data are the mean ±S.E. of three experimentsperformed in triplicate. The results for the compound of Example 6 areshown in Table 2. In this assay forskolin (FSK) raises the level of cAMPabove the basal level (BSL). The addition of anadamide (ANM) inhibitsthe increase of cAMP induced by the forskolin. The compound of Example 6inhibits the biological; action of anandamide, i.e., negates thedecrease in cAMP caused by anandamide, with an IC₅₀ of approximately 500nM.

                  TABLE 2                                                         ______________________________________                                                          cAMP Accumulation                                           Sample            pM/mL                                                       ______________________________________                                        Baseline          <5                                                          Forskolin (FSK)   30                                                          Anandamine (ANM) (1 μM)                                                                      <5                                                          FSK + ANM         5                                                           FSK + Cmpd. 6 (100 μM)                                                                       35                                                          Cmpd. 6 (100 μM)                                                                             5                                                           FSK + ANM + Cmpd. 6                                                           Cmpd. 6 (10 nM)   5                                                           Cmpd. 6 (100 nM)  10                                                          Cmpd. 6 (1 μM) 45                                                          Cmpd. 6 (10 μM)                                                                              65                                                          Cmpd. 6 (100 μM)                                                                             75                                                          ______________________________________                                    

Effect on N-type Calcium Channel Currents

In this series of experiments, it is demonstrated that compounds offormula I, not only bind the CB-1 receptor and inhibit the signaltransduction pathway of CB-1, when activated by its endogenous ligand,anandamide, but in addition, effect other nerve cell organelles undercontrol of the CB-1 signaling pathway in vitro. Specifically, thecompounds of formula I open the N-type calcium channels, which areclosed by either anandamide or the cannabinoids (see: Mackie, K. andHille, B., Proc. Natl. Acad. Sci., 89, p.3825-3829 (1992)).

Materials

DMEM was obtained from Biowhittaker and GIBCO, FBS from HyClone, bovineserum albumin (fatty-acid free), dimethylsulfoxide, and NEM from Sigma,PTX from List, ω-CgTX from Peninsula Labs, and tetrodotoxin fromCalbiochem. WIN 55,212-2 was a gift from Sterling Research Group. CP55,940 was a gift from Pfizer Central Research. Anandamide wassynthesized as described previously. Purity was monitored using thinlayer chromatography with an elution system of petroleumether/ether/methanol (in a ratio of 6:40:4). Anandamide migrated as asingle spot with R_(F) of 0.5, as expected.

Cell Culture and Preparation

N18 (neuroblastoma cell line) cells (passages 32-41) were grown on glasscoverslip fragments in DMEM plus 5% (fetal bovine serum) (FBS, usingstandard cell culture techniques. Six to 14 days before recording, cellswere "differentiated" by changing the medium to DMEM plus 0.5% FBS plus2% dimethylsulfoxide. In PTX (Pertussis Toxin) experiments,differentiated cells were grown for an additional 16-20 hours in mediumcontaining 500 ng/ml PTX. Control cells were treated identically, exceptthat neurons were provided by M. S. Shapiro (University of Washington,Seattle, Wash.).

Current Recording

Currents were recorded using the whole-cell voltage-clamp technique.Pipettes were pulled from hematocrit glass (VWR) and fire polished. Thepipette solution contained (in mM) 100 CsCl, 10 EGTA, 5 MgCl₂, 40 HEPES,3 Na₂ ATP, and 0.2 GTP, pH 7.30 with CsOH. For recording, a coverslipcontaining cells was transferred to the recording chamber (200 μl) andconstantly perfused at a rate of 1-2 ml/min with an external solutioncontaining (in mM) 160 NaCl, 5 CaCl₂, 4 KCl, 1 MgCl₂, 10 HEPES, and 8glucose, pH 7.35 with NaOH. Tetrodotoxin (200 nM) was added to blockvoltage-gated sodium currents, and bovine serum albumin (3 μM) waspresent in all recording solutions to decrease adsorption ofcannabinoids. Subsequently the cannabinoid agonist WIN 55,212 and thecompounds of this invention were added. I_(Ca) was measured near the endof a 25-msec depolarizing pulse to 0 mV and was defined as thatcomponent of the current sensitive to 100 μM CdCl₂. Solution reservoirswere selected by means of a series of solenoid valves, and solutionchanges were accomplished in <1 min. In all experiments the cells wereheld under voltage clamp at a holding potential of -65 mV. Voltageprotocols were generated and data were digitized, recorded, and analyzedusing BASIC-FASTLAB (Indec Systems, Capitola, Calif.). Currents weresampled at 4 kHz and junction potentials are uncorrected. To control forpotential response variations with passage number and duration ofdifferentiation, experimental and control measurements were alternatedwhenever possible. Where appropriate, data are expressed asmean±standard error. [It has been shown in this type of experiment thatWIN 55,212 (used for convenience) acts the same as anandamide, see:Felder, et al; ibid.]

The data from this experiment is shown in Table 3 for the compound ofExample 6. The agonist WIN 55,212 inhibits the N-type calcium channelvia the CB-1 receptor, thus decreasing the current to the voltage clampof -65 pA. The addition of a compound of formula I (Example 6) increasesthis current to -150 pA by opening the N-type calcium channel via theCB-1 receptor. Oxo-M and Cd²⁺ are controls showing the specificity ofthe current regulation and the integrety of the cellular organelles.

Thus, this experiment demonstrates the ability of the compounds offormula I to regulate major nerve cell organelles by antagonizing theactions of either the endogenous ligand, anandamide or agonists invitro.

                  TABLE 3                                                         ______________________________________                                                           Cell Current                                               Sample             pA                                                         ______________________________________                                        Baseline           -150                                                       WIN 55,212 (WIN) (100 nM)                                                                        -60                                                        Cmpd. 6 (1 μM)  -150                                                       WIN + Cmpd. 6      -150                                                       Oxo-M + Cmpd. 6    -60                                                        Cd.sup.++          -60                                                        ______________________________________                                    

In Vivo Effects of Anandamide Antagonists

The following experiment demonstrates the ability of the compounds offormula I to inhibit the sedation caused by anandamide in vivo and in astandard model (Open Field Assay) of mouse behavior, which has been aclassic model for the evaluation of active and useful central nervoussystem agents.

The Open Field Assay evaluates the motion (both horizonal and vertical)of a mouse when placed in a large, open area. Specifically, C57BL/6Jmice are injected with 20 mg/kg (i.p.) of the compound of Example 6, 28minutes before injecting anandamide at 2 mg/kg (i.p.). The mouse isplaced in the center of a large area of a device which measues thenumber of vertical and horizontal movements of the mouse (DigiscanAutomated Open Field). Each test session is of 5 minute duration. At theend of this time period, the mouse is removed from the scanner and therecorded data are automatically analyzed and satisically evaluated.Further details are given in Crawley, J., J. Neurosci., 12(9), p.3380-3391 (1992).

The results of this experiment are shown in Tables 4-5. As seen in theTables, anandamide causes a severe depression and sedation of theanimal's movements, which is reversed by the adminstration of thecompound of Example 6 in regard to Horizontal Exploratory Activity andTotal Distance Exploratory Behavior.

                  TABLE 4                                                         ______________________________________                                        Total Distance Exploratory Behavior                                                             Digiscan Total                                              Sample            Distance/5 min.                                             ______________________________________                                        Vehicle           250*                                                        Vehicle + Anandamide                                                                            50                                                          Cmpd. 6 + Anandamide                                                                            300*                                                        ______________________________________                                         *p < 0.01                                                                

                  TABLE 5                                                         ______________________________________                                        Horizontal Exploratory Behavior                                                                Digiscan Horizontal                                          Sample           Activity/5 min.                                              ______________________________________                                        Vehicle          1100*                                                        Vehicle + Anandamide                                                                           200                                                          Cmpd. 6 + Anandamide                                                                            900*                                                        ______________________________________                                         *p < .05                                                                 

Applications

The compounds of formula I have been shown to bind to the human CB-1receptor and to inhibit the cellular, signal-transduction events evokedby both anandamide and cannabinoids. In vivo, the compounds have beenshown to mitigate the effects of anandamide in the mouse. Due to thelocalization of the CB-1 receptor in the hipocampus and the knownpharmacology of the cannabinoids and their correspondence withanandamide (see: Howlett, A. C., et al., TINS, 13(10),p.420-423.(1990)), mammals, including humans, suffering from symptomologysimilar to that seen with cannibinoids, would recieve benefit from anantagonist of the CB-1 receptor (a compound of formula I). Many diseasestates, although caused by different etiologies, have commonsymptomology. The disease states (listed in the applications, below) arenot caused by the use or abuse of cannibinoids, but since their symptomsare so similar, the endogenous factor anandamide would seem to be alikely contributory factor. Thus, a compound of formula I would be ofbenefit in the treatment of the symptomology of many diseases.Additionally, since treatment of symptomology and treatment of thecausal factors of a disease and their interaction are not wellunderstood or, indeed, may not be separate pathologies, it should not beconstrued that this invention would be solely limited to the treatmentof symptoms.

Symptoms, which would be benecially effected in mammals, includinghumans, with a compound of formula I, would include, but not be limitedto: depression, loss of cognitive function, loss of mental alertness,loss of memory, and loss of sensory perception. These symptoms occur ina variety of pathological states, syndromes, and diseases. The extent,magnitude, particulars of these symptoms vary widely both betweendisease states and between various individuals suffering from one ofthose diseases.

Listed, below, are some of the diseases, from which mammal, including ahuman, would derive a benefit from a compound of formula I: Alzheimer'sDisease, head trauma, senile dementia, brain tumors, and the like.Additional, disease states which may be included in this catagory areelaborated in volumenous references in the art, e.g., see: "Harrison'sPriciples of Internal Medicine", Isselbacher, K. J., et all. Eds. 9thEd., McGraw-Hill Book Co., New York, 1980, Section 3, "Alterations inNervous Function". Again, due to variability of symptoms in any of thesediseases, the decision of the use, dosage level, and protocol oftreatment of a compound of this of this invention is at the discretionof the attending physician.

We claim:
 1. A compound of the formula: ##STR9## Wherein R¹ is cyano;R²and R³ are each individually, C₁ -C₄ alkyl or C₁ -C₄ alkoxy; R⁴ iscarbonyl; and R⁵ is oxygen or sulfur.
 2. The compound of claim 1 whereinR² and R³ are both methoxy and R⁵ is --O--.
 3. The compound of claim 1wherein R² is methyl, R³ is methoxy and R⁵ --O--.
 4. The compound ofclaim 1 wherein R² and R³ are both methoxy and R⁵ is --S--.
 5. Apharmaceutical formulation comprising an effective amount of a compoundof claim 1, and a pharmaceutically acceptable carrier, excipient ordiluent thereof.